Electronic device

ABSTRACT

An electronic device includes a substrate, a first insulating film on the substrate, a second insulating film on the first insulating film, first and second coils respectively in the first and second insulating films, first and second terminals, and first and second connection conductors. The first and second insulating films contact each other so that the first and second coils are magnetically coupled. The first insulating film includes a first non-contact portion not contacting the second insulating film. One of the first and second insulating films includes a second non-contact portion not contacting the first or second insulating film. The first terminal is provided on the first non-contact portion and electrically connected to the first coil. The second terminal is provided on the second non-contact portion and electrically connected to the second coil. The first and second connection conductors are connected to the first and second terminals, respectively.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2020-151324, filed on Sep. 9, 2020; theentire contents of which are incorporated herein by reference.

FIELD

Embodiments relate to an electronic device.

BACKGROUND

An electronic device is required, which can be manufactured with lowcost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view showing an electronic deviceaccording to a first embodiment;

FIGS. 2A and 2B are schematic views showing the electronic deviceaccording to the first embodiment;

FIGS. 3A and 3B are schematic cross-sectional views showing theelectronic device according to the first embodiment;

FIGS. 4A to 5C are schematic cross-sectional views showing manufacturingprocesses of the electronic device according to the first embodiment;

FIG. 6 is a schematic cross-sectional view showing the method formanufacturing the electronic device according to the first embodiment;

FIGS. 7A to 7F are schematic cross-sectional views showing anothermanufacturing process of the electronic device according to the firstembodiment;

FIG. 8 is a schematic cross-sectional view showing an electronic deviceaccording to a modification of the first embodiment;

FIGS. 9A and 9B are schematic cross-sectional views showing anelectronic device according to another modification of the firstembodiment;

FIGS. 10A to 10D are schematic cross-sectional views showing othermanufacturing processes of the electronic devices according to the firstembodiment;

FIGS. 11A and 11B are schematic cross-sectional views showing electronicdevices according to a second embodiment;

FIGS. 12A to 12C are schematic cross-sectional views showingmanufacturing processes of the electronic device according to the secondembodiment;

FIG. 13 is a schematic cross-sectional view showing an electronic deviceaccording to a first modification of the second embodiment;

FIGS. 14A and 14B are schematic cross-sectional views showing electronicdevices according to a second modification of the second embodiment;

FIG. 15 is a schematic cross-sectional view showing an electronic deviceaccording to a third modification of the second embodiment;

FIGS. 16A and 16B are schematic cross-sectional views showing electronicdevices according to a fourth modification of the second embodiment;

FIG. 17 is a schematic cross-sectional view showing an electronic deviceaccording to a third embodiment;

FIGS. 18A to 19C are schematic cross-sectional views showingmanufacturing processes of the electronic device according to the thirdembodiment;

FIG. 20 is a schematic cross-sectional view showing an electronic deviceaccording to a modification of the third embodiment;

FIG. 21 is a schematic cross-sectional view showing an electronic deviceaccording to a fourth embodiment; and

FIG. 22 is a circuit diagram showing the electronic device according tothe fourth embodiment.

DETAILED DESCRIPTION

According to one embodiment, an electronic device includes a firstsubstrate, a first insulating film provided on the first substrate, afirst coil provided in the first insulating film, a second insulatingfilm provided on the first insulating film, a second coil provided inthe second insulating film, first and second terminals, first and secondconnection conductors. The first insulating film and the secondinsulating film contact each other so that the first coil and the secondcoil are magnetically coupled. The second insulating film has a frontsurface contacting the first insulating film. The second insulating filmcontacts a front surface of the first insulating film. The firstinsulating film includes a first non-contact portion not contacting thesecond insulating film. One of the first and second insulating filmsincludes a second non-contact portion not contacting the second or firstinsulating film. The first terminal is provided on the front surface ofthe first insulating film at the first non-contact portion. The firstterminal is electrically connected to the first coil. The secondterminal is provided on the front surface of the first or secondinsulating film at the second non-contact portion. The second terminalis electrically connected to the second coil. The first connectionconductor is connected to the first terminal. The first connectionconductor is electrically connected to the first coil via the firstterminal. The second connection conductor is connected to the secondterminal. The second connection conductor is electrically connected tothe second coil via the second terminal.

Embodiments will now be described with reference to the drawings. Thesame portions inside the drawings are marked with the same numerals; adetailed description is omitted as appropriate; and the differentportions are described. The drawings are schematic or conceptual; andthe relationships between the thicknesses and widths of portions, theproportions of sizes between portions, etc., are not necessarily thesame as the actual values thereof. The dimensions and/or the proportionsmay be illustrated differently between the drawings, even in the casewhere the same portion is illustrated.

There are cases where the dispositions of the components are describedusing the directions of XYZ axes shown in the drawings. The X-axis, theY-axis, and the Z-axis are orthogonal to each other. Hereinbelow, thedirections of the X-axis, the Y-axis, and the Z-axis are described as anX-direction, a Y-direction, and a Z-direction. Also, there are caseswhere the Z-direction is described as upward and the direction oppositeto the Z-direction is described as downward.

First Embodiment

FIG. 1 is a schematic cross-sectional view showing an electronic device1 according to a first embodiment. The electronic device 1 is, forexample, a magnetic coupler. The electronic device 1 includes, forexample, a first inductor chip Ci1 and a second inductor chip Ci2.

The first inductor chip Ci1 includes a first substrate 10, a firstinsulating film 13, and a first coil 15. The first substrate 10 is, forexample, a silicon substrate. The first substrate 10 has a frontsurface, and has a back surface at the side opposite to the frontsurface. The first insulating film 13 is provided on the front surfaceof the first substrate 10. The first insulating film 13 is, for example,a silicon oxide film. The first coil 15 is provided in the firstinsulating film 13. The first coil 15 is, for example, a planar coil.The first coil 15 includes, for example, copper.

The second inductor chip Ci2 includes a second substrate 20, a secondinsulating film 23, and a second coil 25. The second substrate 20 is,for example, a silicon substrate. The second substrate 20 has a frontsurface, and has a back surface at the side opposite to the frontsurface. The second insulating film 23 is provided on the front surfaceof the second substrate 20. The second insulating film 23 is, forexample, a silicon oxide film. The second coil 25 is provided in thesecond insulating film 23. The second coil 25 is, for example, a planarcoil. The second coil 25 includes, for example, copper.

The first inductor chip Ci1 and the second inductor chip Ci2 are bondedso that the first coil 15 and the second coil 25 are magneticallycoupled. For example, the first insulating film 13 and the secondinsulating film 23 contact each other at a portion where the first coil15 and the second coil 25 are magnetically coupled.

The first insulating film 13 has a front surface, and has a back surfaceat the side opposite to the front surface. The first insulating film 13contacts the first substrate 10 at the back surface side of the firstinsulating film 13 and contacts the second insulating film 23 at thefront surface side of the first insulating film 13. The secondinsulating film 23 contacts the second substrate 20 at the back surfaceside of the second insulating film 23 and contacts the first insulatingfilm 13 at the front surface side of the second insulating film 23.

The electronic device 1 further includes a first connection conductor30, a second connection conductor 40, a first external terminal 50, asecond external terminal 60, and a resin member 70.

The first connection conductor 30 is electrically connected to the firstcoil 15 and the first external terminal 50. The second connectionconductor 40 is electrically connected to the second coil 25 and thesecond external terminal 60.

As shown in FIG. 1 , the first inductor chip Ci1 and the second inductorchip Ci2 are sealed between the first external terminal 50 and thesecond external terminal 60 by the resin member 70. The first externalterminal 50 and the second external terminal 60 are, for example, metalplates including copper. The resin member 70 is, for example, an epoxyresin.

The first inductor chip Ci1 is provided between the second externalterminal 60 and the second inductor chip Ci2. The second inductor chipCi2 is provided between the first external terminal 50 and the firstinductor chip Ci1.

The first inductor chip Ci1 further includes a first connection terminal17. The first connection terminal 17 is provided at the front surfaceside of the first insulating film 13. The first connection terminal 17is provided at a portion of the first insulating film 13 not contactingthe second insulating film 23. The first coil 15 is electricallyconnected to the first connection terminal 17 via a connection memberprovided in the first insulating film 13. The first connection conductor30 extends in the resin member 70 and is electrically connected to thefirst connection terminal 17. The first connection conductor 30 is, forexample, a contact plug including copper.

The second inductor chip Ci2 further includes a second connectionterminal 27. The second insulating film 23 has a front surface, and hasa back surface at the side opposite to the front surface. The secondconnection terminal 27 is provided at the front surface side of thesecond insulating film 23. The second connection terminal 27 is providedat a portion of the second insulating film 23 not contacting the firstinsulating film 13. The second coil 25 is electrically connected to thesecond connection terminal 27 via a connection member provided in thesecond insulating film 23. The second connection conductor 40 extends inthe resin member 70 and is electrically connected to the secondconnection terminal 27. The second connection conductor 40 is, forexample, a contact plug including copper.

FIGS. 2A and 2B are schematic views showing the electronic device 1according to the first embodiment. FIG. 2A is a plan view illustratingthe first coil 15. FIG. 2A is a cross section along line A-A shown inFIG. 2B. FIG. 2B is a cross-sectional view showing the first inductorchip Ci1.

As shown in FIG. 2A, the first coil 15 is, for example, a spiral-shapedplanar coil. The first coil 15 includes a coil portion 15 m, connectinglines 15 a and 15 b, and connection pads 15 c and 15 d. The connectinglines 15 a and 15 b are connected respectively to two ends of the coilportion 15 m. The connection pad 15 c is electrically connected to thecoil portion 15 m via the connecting line 15 a. The connection pad 15 dis electrically connected to the coil portion 15 m via the connectingline 15 b. For example, the coil portion 15 m, the connecting line 15 a,and the connection pad 15 c are provided at the same level in theZ-direction in the first insulating film 13; and the connecting line 15b and the connection pad 15 d are provided at a lower level.

The shape of the coil portion 15 m is not limited to circular and maybe, for example, polygonal. The coil portion 15 m is not limited to aplanar coil and may be a multilevel coil.

As shown in FIG. 2B, a first connection terminal 17 a is exposed at thefront surface side of the first insulating film 13. For example, thefirst connection terminal 17 a is electrically connected to the firstcoil 15 via a contact plug 19 a. For example, the contact plug 19 a isconnected to the connection pad 15 c.

The first inductor chip Ci1 includes, for example, the two firstconnection terminals 17 a and 17 b (not illustrated) electricallyconnected to the first coil 15. As shown in FIG. 2B, for example, thefirst connection terminal 17 a is electrically connected to theconnection pad 15 c of the first coil 15 via the contact plug 19 a. Thefirst connection terminal 17 b (not illustrated) is electricallyconnected to the connection pad 15 d of the first coil 15 via anothercontact plug 19 b (not illustrated). For example, the contact plugs 19 aand 19 b also may be connected to a circuit (not-illustrated) providedbelow the contact plugs 19 a and 19 b.

The second inductor chip Ci2 has the same configuration as the firstinductor chip Ci1 shown in FIGS. 2A and 2B. The coil diameter of thesecond coil 25 may be equal to or different from a coil diameter D1 ofthe first coil 15. From the perspective of fluctuation when mounting, itis favorable for one of the coil diameters to be larger than the other.

FIGS. 3A and 3B are schematic cross-sectional views showing theelectronic device 1 according to the first embodiment. FIGS. 3A and 3Bare schematic cross-sectional views illustrating the mountedconfiguration of the electronic device 1.

FIG. 3A is a cross-sectional view along line B-B shown in FIG. 3B. Thefirst inductor chip Ci1 and the second inductor chip Ci2 are notillustrated in FIG. 3A.

As shown in FIG. 3A, the electronic device 1 is mounted in a horizontalorientation on a circuit board 80. For example, the direction from thesecond external terminal 60 toward the first external terminal 50 isparallel to the upper surface of the circuit board 80. The firstexternal terminal 50 is connected to a mount pad 81 via a connectionmember 91, e.g., a solder material. The second external terminal 60 isconnected to a mount pad 85 via a connection member 95, e.g., a soldermaterial.

As shown in FIG. 3B, the electronic device 1 is mounted via theconnection members 91, 93, 95, and 97 such as solder materials, etc., onthe mount pads 81, 83, 85, and 87 provided on the circuit board 80. Theelectronic device 1 includes, for example, a first external terminal 50a, a first external terminal 50 b, a second external terminal 60 a, anda second external terminal 60 b. Although one of the first externalterminal 50 a or 50 b is described as the first external terminal 50 forconvenience in the specification, the first coil 15 and the second coil25 each are connected to one pair of external terminals. This is similarfor the other components in connection with the first and second coils15 and 25.

The first external terminal 50 a is electrically connected to the firstconnection terminal 17 a of the first inductor chip Ci1 (referring toFIG. 2B) via the first connection conductor 30 (referring to FIG. 1 ).Also, the first external terminal 50 a is electrically connected to aninterconnect 81 i via the connection member 91 and the mount pad 81.

The first external terminal 50 b is electrically connected to the firstconnection terminal 17 b (not illustrated) of the first inductor chipCi1 via another first connection conductor (not-illustrated). Also, thefirst external terminal 50 b is electrically connected to aninterconnect 83 i via the connection member 93 and the mount pad 83.

The first coil 15 of the first inductor chip Ci1 is electricallyconnected to the interconnect 81 i and the interconnect 83 i via thefirst external terminals 50 a and 50 b. Also, the first coil 15 iselectrically connected to a primary side circuit (not-illustrated) viathe interconnect 81 i and the interconnect 83 i.

The second external terminal 60 a is electrically connected to a secondconnection terminal 27 a of the second inductor chip Ci2 (referring toFIG. 1 ) via the second connection conductor 40 (referring to FIG. 1 ).Also, the second external terminal 60 a is electrically connected to aninterconnect 85 i via the connection member 95 and the mount pad 85.

The second external terminal 60 b is electrically connected to a secondconnection terminal 27 b (not illustrated) of the second inductor chipCi2 via another second connection conductor (not-illustrated). Also, thesecond external terminal 60 b is electrically connected to aninterconnect 87 i via the connection member 97 and the mount pad 87.

The second coil 25 of the second inductor chip Ci2 is electricallyconnected to the interconnect 85 i and the interconnect 87 i via thesecond external terminals 60 a and 60 b. Also, the second coil 25 iselectrically connected to a secondary side circuit (not-illustrated) viathe interconnect 85 i and the interconnect 87 i.

Thus, the electronic device 1 includes one pair of first externalterminals 50 electrically connected to the first coil 15, and the otherpair of second external terminals 60 electrically connected to thesecond coil 25. In the description hereinbelow, only one of the pair ofterminals is mentioned for convenience, which are connected to each ofthe first and second coils 15 and 25, and a description of the other isomitted.

A method for manufacturing the electronic device 1 will now be describedwith reference to FIGS. 4A to 5C. FIGS. 4A to 5C are schematiccross-sectional views showing manufacturing processes of the electronicdevice 1 according to the first embodiment.

As shown in FIG. 4A, multiple first coils 15 are formed on the firstsubstrate 10. For example, the first coil 15 is formed using asemiconductor wafer processing method. After the insulating film 13 a isformed on the first substrate 10, for example, the first coil 15 isformed by filling a copper material into a spiral-shaped recess formedin an insulating film 13 a. The first connection terminal 17 is formedafter forming an insulating film 13 b to bury the first coil 15.

The insulating films 13 a and 13 b are, for example, silicon oxide filmsand are formed using CVD (Chemical Vapor Deposition). The first coil 15is formed, for example, using plating. Hereinbelow, the first insulatingfilm 13 includes the insulating films 13 a and 13 b which are joinedtogether.

As shown in FIG. 4B, a resin sheet 103 is adhered on the firstinsulating film 13. The resin sheet 103 is, for example, a dicing sheet.

As shown in FIG. 4C, the multiple first inductor chips Ci1 are formed bydividing the first substrate 10 and the first insulating film 13 on theresin sheet 103. For example, the first substrate 10 and the firstinsulating film 13 are cut using a dicing blade from the back surfaceside of the first substrate 10.

As shown in FIG. 4D, a space SP1 is provided between the adjacent firstinductor chips Ci1 by expanding the resin sheet 103.

As shown in FIG. 5A, a resin sheet 105 is adhered to the back surface ofthe first substrate 10 while the multiple first inductor chips Ci1 areheld on the resin sheet 103.

As shown in FIG. 5B, the surface of the first insulating film 13 isexposed at each of the multiple first inductor chips Ci1 by peeling theresin sheet 103. Continuing, the surfaces of the first insulating films13 are cleaned by, for example, oxygen plasma, etc., while the multiplefirst inductor chips Ci1 are held on the resin sheet 105. Thereby,organic substances such as the pressure sensitive adhesive are removed,which are adhered to the surfaces of the first insulating films 13 andlike.

As shown in FIG. 5C, the second inductor chips Ci2 are bondedrespectively to the multiple first inductor chips Ci1. The secondinductor chip Ci2 is connected to the first inductor chip Ci1 so thatthe first coil 15 and the second coil 25 are magnetically coupled. Forexample, the second inductor chips Ci2 are formed separately through theprocesses of FIGS. 4A to 4D.

The first inductor chip Ci1 and the second inductor chip Ci2 are bondedby causing the first insulating film 13 and the second insulating film23 to contact each other. The first connection terminal 17 and thesecond connection terminal 27 (referring to FIG. 1 ) are exposed bybonding so that the second inductor chip Ci2 is shifted in thehorizontal direction with respect to the first inductor chip Ci1.

FIG. 6 is a schematic cross-sectional view showing the method formanufacturing the electronic device 1 according to the first embodiment.FIG. 6 is a schematic view showing the bonding method between the firstinsulating film 13 and the second insulating film 23.

As shown in FIG. 6 , for example, the bonding between the firstinsulating film 13 and the second insulating film 23 is performed by atwo-stage process of a temporary bonding and a main bonding. In otherwords, the first insulating film 13 and the second insulating film 23are temporarily bonded via hydroxide groups linked to dangling bonds atthe surfaces of the first and second insulating films 13 and 23.Continuing, the hydroxide is removed as moisture by heat treatment, andthe dangling bonds of the first insulating film 13 and the danglingbonds of the second insulating film 23 are polymerized via oxygen (themain bonding).

FIGS. 7A to 7F are schematic cross-sectional views showing anothermanufacturing process of the electronic device 1 according to the firstembodiment. FIGS. 7A to 7F illustrate processes of bonding the secondinductor chip Ci2 to the first inductor chip Ci1.

As shown in FIG. 7A, the second inductor chips Ci2 that are held on aresin sheet 106 are disposed to face the first inductor chips Ci1 heldon the resin sheet 105. The first inductor chips Ci1 each have a backsurface attached to the resin sheet 105. The second inductor chips eachhave a back surface attached to the resin sheet 106. The resin sheets105 and 106 are held respectively by expansion rings ER1 and ER2.

The second inductor chips Ci2 are disposed such that the secondinsulating films 23 face the first insulating films 13 of the firstinductor chips Ci1, respectively. For example, plasma activationprocessing is performed for the surfaces of the first insulating films13 and the surfaces of the second insulating films 23. For example, byexposing the surfaces of the first insulating films 13 and the surfacesof the second insulating films 23 to plasma-excited argon or oxygen, theforeign matter is removed at the surfaces, and the dangling bonds of thesurface atoms are activated.

The second inductor chips Ci2 are respectively located at prescribedrelative positions with respect to the first inductor chips Ci1. Forexample, the second inductor chip Ci2 to be bonded is moved to aprescribed position above the first inductor chip Ci1 by an alignmentmechanism adjusting the position of the expansion ring ER1(not-illustrated).

As shown in FIG. 7B, a pressing mechanism HJ and a compression bondingmechanism PJ press the resin sheet 106 down at the side opposite to thesurface holding the second inductor chips Ci2, and make the spacingnarrow between the second inductor chips Ci2 and the first inductorchips Ci1.

The compression bonding mechanism PJ is provided at the center of thepressing mechanism HJ. For example, the pressing mechanism HJ narrowsthe spacing between the first inductor chip Ci1 and the second inductorchip Ci2 by pressing the back surface side of the second inductor chipCi2. The compression bonding mechanism PJ applies pressure to the backsurface of the second inductor chip Ci2 to be bonded. The compressionbonding mechanism PJ includes a press pin PJ1 and a presser PJ2. The tipof the press pin PJ1 is positioned at the center of the presser PJ2 andhas a smaller surface area than the chip size of the second inductorchip Ci2.

As shown in FIG. 7C, the compression bonding mechanism PJ moves downwardfurther with respect to the pressing mechanism HJ, thereby the secondinductor chip Ci2, which is to be bonded, contacts the first inductorchip Ci1. For example, at the lower surface of the compression bondingmechanism PJ that contacts the resin sheet 106, the tip of the press pinPJ1 is positioned at a higher level than the lower surface of thepresser PJ2.

The first insulating film 13 and the second insulating film 23 aretemporarily bonded by making the first inductor chip Ci1 and the secondinductor chip Ci2 contact to each other. For example, the activatedsurfaces of the first insulating film 13 and the second insulating film23 are bonded via hydrogen bonds between hydroxide groups and watermolecules.

As shown in FIG. 7D, the presser PJ2 of the compression bondingmechanism PJ is raised after lowering the press pin PJ1 to press thesecond inductor chip Ci2 that is to be bonded. Thereby, the resin sheet106 is peeled from the back surface of the second inductor chip Ci2other than the portion pressed by the tip of the press pin PJ1.

As shown in FIG. 7E, the second inductor chip Ci2 is released from thepressing by raising the press pin PJ1 of the compression bondingmechanism PJ. The resin sheet 106 is peeled from the second inductorchip Ci2 by the tension of the resin sheet 106. At this time, the resinsheet 106 can be peeled easily without the temporary bond separatedbetween the first inductor chip Ci1 and the second inductor chip Ci2,because the resin sheet 106 has been peeled from the back surface of thesecond inductor chip Ci2 other than the portion pressed by the tip ofthe press pin PJ1.

As shown in FIG. 7F, the second inductor chips Ci2 are bonded on all ofthe first inductor chips Ci1 by repeating the bonding process describedabove. Subsequently, the main bonding of the first inductor chips Ci1and the second inductor chips Ci2 is performed by heat treatment whilepressing the back surfaces of the second inductor chips Ci2. The resinsheet 105 that holds the first inductor chips Ci1 and the secondinductor chips Ci2 in the temporary bonding state is placed, forexample, on a hotplate, and the moisture is removed from the bondinginterface between the first insulating film 13 and the second insulatingfilm 23 by performing heat treatment at a temperature of not more than250° C.

Thus, a magnetic coupler can be easily obtained by directly bonding thefirst insulating film 13 and the second insulating film 23. In theembodiment, it is easy to increase the thickness of the insulating filmbetween the first coil 15 and the second coil 25; and the breakdownvoltage of the magnetic coupler can be increased.

For example, in a method in which the first coil 15 and the second coil25 are formed in order on the substrate 10, the manufacturing processesare increased, and the manufacturing cost is increased. Also, as theinsulating film between the first coil 15 and the second coil 25 isincreased, the warp of the wafer due to the stress of the insulatingfilm increases, and the manufacturing yield decreases. In other words,in the manufacturing method according to the embodiment, themanufacturing cost can be reduced and the manufacturing yield can beincreased.

Also, the connections between the first external terminal 50 and thefirst coil 15 and between the second coil 25 and the second externalterminal 60 are easier because the first connection terminal 17 and thesecond connection terminal 27 are exposed at the surfaces of the firstand second insulating films 13 and 23.

FIG. 8 is a schematic cross-sectional view showing an electronic device2 according to a modification of the first embodiment. The electronicdevice 2 has a configuration in which the first inductor chip Ci1 andthe second inductor chip Ci2 are bonded, and the first coil 15 and thesecond coil 25 are magnetically coupled.

For example, the first inductor chip Ci1 and the second inductor chipCi2 are mounted on a lead 53M and sealed with a resin member 73. A firstexternal terminal 53 and a second external terminal 63 are provided toextend from the resin member 73. The first external terminal 53 islinked to the lead 53M. The first external terminal 53, the secondexternal terminal 63, and the lead 53M are, for example, metal platesincluding copper. The resin member 73 is, for example, an epoxy resin.

For example, the back surface side of the first substrate 10 is mountedon the lead 53M. A first connection conductor 33 electrically connectsthe first connection terminal 17 of the first inductor chip Ci1(referring to FIG. 1 ) and the first external terminal 53. A secondconnection conductor 43 electrically connects the second connectionterminal 27 of the second inductor chip Ci2 (referring to FIG. 1 ) andthe second external terminal 63.

The electronic device 2 includes a plurality of first connectionterminals 17, a plurality of second connection terminals 27, a pluralityof first external terminals 53, and a plurality of second externalterminals 63; and each plurality is arranged in, for example, theY-direction. The first connection terminals 17 are connectedrespectively to the first external terminals 53. The second connectionterminals 27 are connected respectively to the second external terminals63. The first connection conductors 33 and the second connectionconductors 43 are, for example, metal wires.

FIGS. 9A and 9B are schematic cross-sectional views showing anelectronic device 3 according to another modification of the firstembodiment. FIG. 9A is a schematic cross-sectional view showing theconfiguration of the electronic device 3. FIG. 9B is a schematic viewillustrating the mounted configuration of the electronic device 3.

As shown in FIG. 9A, the electronic device 3 has a configuration inwhich the first inductor chip Ci1 and the second inductor chip Ci2 arebonded, and the first coil 15 and the second coil 25 are magneticallycoupled. The first inductor chip Ci1 and the second inductor chip Ci2are sealed in a resin member 75. The resin member 75 is, for example, anepoxy resin.

The electronic device 3 further includes the first external terminal 50,the second external terminal 60, a first connection conductor 35, asecond connection conductor 45, a connection interconnect 37, a thirdconnection conductor 39, and a heat dissipation plate 65.

The first connection conductor 35, the second connection conductor 45,and the third connection conductor 39 are, for example, contact plugsthat include copper and extend inside the resin member 75. The firstexternal terminal 50, the second external terminal 60, the connectioninterconnect 37, and the heat dissipation plate 65 are, for example,metal plates including copper and are provided on the outer surface ofthe resin member 75.

The resin member 75 includes, for example, an upper surface and a lowersurface crossing the direction from the first inductor chip Ci1 towardthe second inductor chip Ci2 (in the Z-direction). The first externalterminal 50 and the second external terminal 60 are provided on thelower surface of the resin member 75. The connection interconnect 37 andthe heat dissipation plate 65 are provided on the upper surface of theresin member 75.

The first connection conductor 35 extends in the Z-direction through theresin member 75 and electrically connects the connection interconnect 37and the first connection terminal 17 of the first inductor chip Ci1. Thethird connection conductor 39 extends in the Z-direction through theresin member 75 and electrically connects the connection interconnect 37and the first external terminal 50. In the example, the first externalterminal 50 is electrically connected to the first connection terminal17 via the first connection conductor 35, the connection interconnect37, and the third connection conductor 39.

The second connection conductor 45 extends in the Z-direction throughthe resin member 75 and electrically connects the second externalterminal 60 and the second connection terminal 27 of the second inductorchip Ci2.

As shown in FIG. 9B, the electronic device 3 is horizontally mounted onthe circuit board 80. For example, the direction from the first externalterminal 50 toward the second external terminal 60 (the X-direction) isparallel to the upper surface of the circuit board 80. For example, thefirst external terminal 50 is connected to the mount pad 81 via theconnection member 91. The second external terminal 60 is connected tothe mount pad 85 via the connection member 95.

In the electronic devices 1 to 3, for example, the first substrate 10and the second substrate 20 each include an electronic circuit(referring to FIG. 21 ). The electronic circuits are electricallyconnected respectively to the first and second coils 15 and 25. Also,the electronic circuits are electrically connected respectively to theexternal terminal 50 via the first connection conductor 30 and to theexternal terminal 60 via the second connection conductor 40 (referringto FIG. 1 ).

Another method for manufacturing the electronic devices 1 to 3 accordingto the first embodiment will now be described with reference to FIGS.10A to 10D. FIGS. 10A to 10D are schematic cross-sectional views showingother manufacturing processes of the electronic devices 1 to 3.

As shown in FIG. 10A, multiple first coils 15 are formed on the firstsubstrate 10. The first coils 15 are formed respectively in the firstinsulating films 13. The first insulating films 13 are separated fromeach other; for example, a dicing region DR is formed between theadjacent first insulating films 13.

As shown in FIG. 10B, the first substrate 10 is half-cut in the dicingregion DR. The first substrate 10 is partially cut using, for example, adicing blade. The dicing line DL is formed with the trench-shape in thefirst substrate 10.

As shown in FIG. 10C, the second inductor chips Ci2 are bondedrespectively to the multiple first insulating films 13. The secondinsulating film 23 of the second inductor chip Ci2 is directly bonded tothe first insulating film 13 so that the first coil 15 and the secondcoil 25 are magnetically coupled. The first insulating film 13 and thesecond insulating film 23 are bonded using, for example, the methodshown in FIG. 6 .

As shown in FIG. 10D, the first inductor chips Ci1 are formed by dicingthe first substrate 10. For example, the first substrate 10 is thinnedto a prescribed thickness by grinding or polishing the back surfaceside, and divided into multiple chips. In other words, the firstsubstrate 10 is divided into multiple chips by the dicing line DL.

In the electronic devices 1 to 3 according to the first embodiment, thefirst coil 15 and the second coil 25 are provided between the firstsubstrate 10 and the second substrate 20. When the first substrate 10and the second substrate 20 are electrically conductive, the first coil15 and the second coil 25 are shielded from external electromagneticwaves. In other words, the electronic devices 1 to 3 can be configuredto prevent the disturbance due to electromagnetic waves.

Second Embodiment

FIGS. 11A and 11B are schematic cross-sectional views showing electronicdevices 4A and 4B according to the second embodiment.

As shown in FIG. 11A, the electronic device 4A has a structure in whichthe second inductor chip Ci2 is bonded on a third inductor chip Ci3including the first coil 15. The electronic device 4A is configured sothat the first coil 15 and the second coil 25 are magnetically coupled.

The third inductor chip Ci3 further includes the first insulating film13, a first substrate 100, a bonding layer 107, a first connectionterminal 113, a second connection terminal 115, a third connectionterminal 117, and a connecting line 119.

The first substrate 100 is, for example, a silicon substrate. The firstsubstrate 100 has a front surface, and has a back surface at a sideopposite to the front surface. The first insulating film 13 is providedon the front surface of the first substrate 100. The bonding layer 107is provided on the back surface side of the first substrate 100. Thebonding layer 107 is, for example, a metal layer including titanium,nickel, gold, etc.

The first connection terminal 113 is provided at the front surface sideof the first insulating film 13. The first coil 15 is provided in thefirst insulating film 13 and is electrically connected to the firstconnection terminal 113 via, for example, the connecting line 15 b andthe connection pad 15 d (referring to FIG. 2A).

The second connection terminal 115 and the third connection terminal 117are provided at the front surface side of the first insulating film 13.For example, the second connection terminal 115 and the third connectionterminal 117 are electrically connected via the connecting line 119. Thethird connection terminal 117 is provided between the first connectionterminal 113 and the second connection terminal 115. The firstconnection terminal 113, the second connection terminal 115, the thirdconnection terminal 117, and the connecting line 119 include, forexample, copper. The connecting line 119 includes, for example, the samematerial as the first coil 15.

The second inductor chip Ci2 is provided on the third inductor chip Ci3by bonding the first insulating film 13 and the second insulating film23. Another second connection terminal 127 and the third connectionterminal 117 are bonded between the second inductor chip Ci2 and thethird inductor chip Ci3. The second coil 25 is electrically connected tothe second connection terminal 115 of the third inductor chip Ci3 viathe other second connection terminal 127, the third connection terminal117, and the connecting line 119.

The first connection terminal 113 and the second connection terminal 115are exposed at the front surface of the first insulating film 13 outsidethe region where the first insulating film 13 and the second insulatingfilm 23 are bonded.

In the electronic device 4B shown in FIG. 11B, a fourth inductor chipCi4 that includes the second coil 25 is bonded on the third inductorchip Ci3. The electronic device 4B also is configured so that the firstcoil 15 and the second coil 25 are magnetically coupled.

The fourth inductor chip Ci4 includes a second substrate 120 and asecond insulating film 123. The second substrate 120 is, for example, asilicon substrate. The second insulating film 123 is provided on thesecond substrate 120 and includes the second coil 25. The secondinsulating film 123 is, for example, a silicon oxide film. The secondinsulating film 123 includes a back surface contacting the secondsubstrate 120, and a front surface at the side opposite to the backsurface. The second coil 25 is electrically connected to the secondconnection terminal 127 provided at the front surface side of the secondinsulating film 123.

The fourth inductor chip Ci4 is provided on the third inductor chip Ci3by bonding the first insulating film 13 and the second insulating film123. The second connection terminal 127 and the third connectionterminal 117 are bonded between the fourth inductor chip Ci4 and thethird inductor chip Ci3.

In the example, the first insulating film 13 of the third inductor chipCi3 has a thickness T1 in the Z-direction. The second insulating film123 of the fourth inductor chip Ci4 has a thickness T2 in theZ-direction. For example, the second insulating film 123 is configuredsuch that the thickness T2 is different from the thickness T1. Forexample, the thickness T2 in the Z-direction of the second insulatingfilm 123 is less than the thickness T1 in the Z-direction of the firstinsulating film 13.

A method for manufacturing the electronic devices 4A and 4B according tothe second embodiment will now be described with reference to FIGS. 12Ato 12C. FIGS. 12A to 12C are schematic cross-sectional views showingmanufacturing processes of the electronic device 4A. The electronicdevice 4B is similarly formed.

As shown in FIG. 12A, the first insulating film 13 that includes thefirst coil 15 and the connecting line 119 is formed on the firstsubstrate 100. The first connection terminal 113, the second connectionterminal 115, and the third connection terminal 117 are formed on thefirst insulating film 13.

For example, the first connection terminal 113 is electrically connectedto the connection pad 15 d of the first coil 15 via the contact plug 19b (referring to FIG. 2A). The first coil 15 is electrically connected tothe first connection terminal 113 via the contact plug 19 b.

For example, the second connection terminal 115 is electricallyconnected to the connecting line 119 via a contact plug 19 c. Forexample, the third connection terminal 117 is electrically connected tothe connecting line 119 via a contact plug 19 d.

For example, the first coil 15, the first connection terminal 113, thesecond connection terminal 115, the third connection terminal 117, andthe connecting line 119 are formed on the first substrate 100 by usingthe semiconductor wafer processing method.

As shown in FIGS. 12B and 12C, the second inductor chip Ci2 and thethird inductor chip Ci3 are bonded after aligning the second inductorchip Ci2 above the third inductor chip Ci3 so that the first coil 15 andthe second coil 25 are magnetically coupled.

In such a case, the second inductor chip Ci2 and the third inductor chipCi3 are bonded by both the bonding of the first insulating film 13 andthe second insulating film 23 and the bonding of the second connectionterminal 127 and the third connection terminal 117. The secondconnection terminal 127 of the second inductor chip Ci2 and the thirdconnection terminal 117 of the third inductor chip Ci3 are metal layerseach including copper; and the both can be bonded by making the cleanedsurfaces contact to each other.

Continuing, the first substrate 100 and the first insulating film 13 arecut into the multiple third inductor chips Ci3 using, for example, adicing blade.

FIG. 13 is a schematic cross-sectional view showing an electronic device5 according to a first modification of the second embodiment. Theelectronic device 5 includes the second inductor chip Ci2 and the thirdinductor chip Ci3. The second inductor chip Ci2 and the third inductorchip Ci3 are bonded so that the first coil 15 and the second coil 25 aremagnetically coupled.

For example, the third inductor chip Ci3 is mounted on a dielectricsubstrate 130 via the bonding layer 107 on the back surface of the thirdinductor chip Ci3 and a connection member 121 such as a solder materialor the like. For example, the third inductor chip Ci3 is mounted on thedielectric substrate 130 after the second inductor chip Ci2 is bonded tothe third inductor chip Ci3.

The dielectric substrate 130 includes bonding pads 131 and 133, a firstexternal terminal 135, and a second external terminal 137. Thedielectric substrate 130 has a front surface, and has a back surface atthe side opposite to the front surface. The first external terminal 135and the second external terminal 137 are provided at the back surfaceside of the dielectric substrate 130. The bonding pads 131 and 133 areprovided at the front surface side of the dielectric substrate 130 wherethe third inductor chip Ci3 is mounted, and are electrically connectedrespectively to the first external terminal 135 and the second externalterminal 137.

The first connection terminal 113 of the third inductor chip Ci3 iselectrically connected to the bonding pad 131 via a first connectionconductor 125. The second connection terminal 115 is electricallyconnected to the bonding pad 133 via a second connection conductor 129.The first connection conductor 125 and the second connection conductor129 are, for example, metal wires including gold (Au), silver (Ag), orcopper (Cu).

The second inductor chip Ci2, the third inductor chip Ci3, the firstconnection conductor 125, and the second connection conductor 129 aresealed on the dielectric substrate 130 by a resin member 160. The resinmember 160 is, for example, an epoxy resin.

Also, in the example, the first coil 15 is electrically connected to thefirst external terminal 135 via the first connection terminal 113 andthe first connection conductor 125. The second coil 25 is electricallyconnected to the second external terminal 137 via the second connectionterminal 115 and the second connection conductor 129.

FIGS. 14A and 14B are schematic cross-sectional views showing electronicdevices 6A and 6B according to a second modification of the secondembodiment. The electronic devices 6A and 6B include the second inductorchip Ci2, the third inductor chip Ci3, and a control chip CC. The secondinductor chip Ci2, the third inductor chip Ci3, and the control chip CCare sealed on the dielectric substrate 130 by the resin member 160. Thecontrol chip CC is, for example, a MOSFET.

In the electronic device 6A shown in FIG. 14A, the third inductor chipCi3 and the control chip CC are mounted on the dielectric substrate 130.The second inductor chip Ci2 is bonded on the third inductor chip Ci3 sothat the first coil 15 and the second coil 25 are magnetically coupled.

For example, the third inductor chip Ci3 is mounted on the dielectricsubstrate 130 after the second inductor chip Ci2 is bonded to the thirdinductor chip Ci3. The control chip CC is mounted on the dielectricsubstrate 130 so that the third inductor chip Ci3 and the control chipCC are arranged on the dielectric substrate 130.

The first connection terminal 113 of the third inductor chip Ci3 iselectrically connected to an input terminal 151 of the control chip CCvia a first connection conductor 141. The second connection terminal 115is electrically connected to the second external terminal 137 via asecond connection conductor 143. The first external terminal 135 iselectrically connected to an output terminal 153 of the control chip CCvia a third connection conductor 145. The first connection conductor141, the second connection conductor 143, and the third connectionconductor 145 are, for example, metal wires.

In the electronic device 6B shown in FIG. 14B, the control chip CC ismounted on the dielectric substrate 130. The third inductor chip Ci3 ismounted on the control chip CC. The second inductor chip Ci2 is bondedon the third inductor chip Ci3 so that the first coil 15 and the secondcoil 25 are magnetically coupled. For example, the third inductor chipCi3 is mounted on the control chip CC after the second inductor chip Ci2is bonded to the third inductor chip Ci3.

The first connection terminal 113 of the third inductor chip Ci3 iselectrically connected to the input terminal 151 of the control chip CCvia the first connection conductor 141. The second connection terminal115 is electrically connected to the second external terminal 137 viathe second connection conductor 143. The output terminal 153 of thecontrol chip CC is electrically connected to the first external terminal135 via the third connection conductor 145. The first connectionconductor 141, the second connection conductor 143, and the thirdconnection conductor 145 are, for example, metal wires.

In the examples described above, the input signal is input from thesecond external terminal 137 to the second inductor chip Ci2. The secondinductor chip Ci2 is provided at the transmitting side. The input signalis transmitted via the magnetic coupling between the second coil 25 ofthe second inductor chip Ci2 and the first coil 15 of the third inductorchip Ci3; and a control signal that corresponds to the input signal isoutput from the first connection terminal 113. The control signal isinput to the control chip CC; and an output signal corresponding to theinput signal is output from the first external terminal 135 that iselectrically connected to the control chip CC.

For example, the electronic devices 6A and 6B act as relays. Forexample, by using a switching element such as a MOSFET or the like asthe control chip CC, the second inductor chip Ci2 is operated as thetransmitting side, and the third inductor chip is operated as thereceiving side. In other words, the control chip CC is controlled by thesignal transmitted from the second inductor chip Ci2 to the thirdinductor chip Ci3, which serves as the gate input of the control chipCC. Thereby, the relay can be configured in which the input side and theoutput side are electrically insulated.

FIG. 15 is a schematic cross-sectional view showing an electronic device7 according to a third modification of the second embodiment. Theelectronic device 7 includes the second inductor chip Ci2 and the thirdinductor chip Ci3. The second inductor chip Ci2 and the third inductorchip Ci3 are bonded so that the first coil 15 and the second coil 25 aremagnetically coupled. The second inductor chip Ci2 and the thirdinductor chip Ci3 are sealed with a resin member 165. The electronicdevice 7 further includes a base 170 for heat dissipation which isconnected to the back surface of the third inductor chip Ci3.

The third inductor chip Ci3 is mounted on the base 170 via a connectionmember 173 after the second inductor chip Ci2 is bonded to the thirdinductor chip Ci3. The base 170 is, for example, a metal plate includingcopper, aluminum, etc. The connection member 173 is a solder materialand like. The connection member 173 may be an insulative paste having ahigh thermal conductivity.

The resin member 165 includes, for example, a front surface thatcontacts the base 170, and a back surface at the side opposite to thefront surface; and a first external terminal 193 and a second externalterminal 195 are provided at the back surface side. The resin member 165is molded to cover the second inductor chip Ci2 and the third inductorchip Ci3 mounted on the base 170. The resin member 165 is, for example,an epoxy resin.

A first connection conductor 183 extends in the resin member 165 andelectrically connects the first external terminal 193 and the firstconnection terminal 113 of the third inductor chip Ci3. A secondconnection conductor 185 extends in the resin member 165 andelectrically connects the first external terminal 195 and the secondconnection terminal 115 of the third inductor chip Ci3. The firstconnection conductor 183 and the second connection conductor 185 are,for example, contact plugs including copper.

FIGS. 16A and 16B are schematic cross-sectional views showing electronicdevices 8A and 8B according to a fourth modification of the secondembodiment. The electronic devices 8A and 8B include the second inductorchip Ci2, the third inductor chip Ci3, and the control chip CC. Thesecond inductor chip Ci2, the third inductor chip Ci3, and the controlchip CC are sealed on the base 170 by the resin member 165. The controlchip CC is a MOSFET. For example, the second inductor chip Ci2 and thethird inductor chip Ci3 serve as a transceiver chip and perform thetransmission of the signal and the ON/OFF control of an output-sidecircuit while being insulated from each other.

In the electronic device 8A shown in FIG. 16A, the third inductor chipCi3 and the control chip CC are respectively mounted on the base 170 viathe connection members 173 and 175 such as solder materials and like.The connection members 173 and 175 may be insulating paste having goodthermal conductivity. The second inductor chip Ci2 is bonded on thethird inductor chip Ci3 so that the first coil 15 and the second coil 25are magnetically coupled.

For example, the third inductor chip Ci3 is mounted on the base 170after the second inductor chip Ci2 is bonded to the third inductor chipCi3. The control chip CC is mounted on the base 170 so that the thirdinductor chip Ci3 and the control chip CC are arranged thereon.

The resin member 165 is molded on the base 170 to cover the secondinductor chip Ci2, the third inductor chip Ci3, and the control chip CC.The resin member 165 includes a front surface that contacts the base170, and a back surface at the side opposite to the front surface.Connection pads 213, 215, and 217 are provided at the back surface sideof the resin member 165.

The electronic device 8A further includes first to fourth connectionconductors 201 to 207. The first to fourth connection conductors 201 to207 are, for example, contact plugs that include copper and extendinside the resin member 165.

The first connection conductor 201 extends in the resin member 165 andelectrically connects the connection pad 213 and the first connectionterminal 113 of the third inductor chip Ci3. The second connectionconductor 203 extends in the resin member 165 and electrically connectsthe connection pad 215 and the second connection terminal 115 of thethird inductor chip Ci3.

The third connection conductor 205 electrically connects the connectionpad 213 and the input terminal 151 of the control chip CC. In otherwords, the first connection terminal 113 of the third inductor chip Ci3is electrically connected to the input terminal 151 of the control chipCC via the first connection conductor 201, the connection pad 213, andthe third connection conductor 205. The fourth connection conductor 207electrically connects the connection pad 217 and the output terminal 153of the control chip CC.

The electronic device 8A further includes a dielectric substrate 220bonded to the back surface side of the resin member 165. The dielectricsubstrate 220 is, for example, a composite substrate including an epoxyresin, etc. The dielectric substrate 220 includes a front surface thatcontacts the resin member 165, and a back surface at the side oppositeto the front surface.

For example, a first external terminal 223 and a second externalterminal 225 are provided at the back surface side of the dielectricsubstrate 220. The dielectric substrate 220 is bonded to the resinmember 165. The first external terminal 223 and the second externalterminal 225 are electrically bonded respectively to the connection pads217 and 215. In other words, the first external terminal 223 iselectrically connected to the output terminal 153 of the control chip CCvia the fourth connection conductor 207. The second external terminal225 is electrically connected to the second connection terminal 115 ofthe third inductor chip Ci3 via the second connection conductor 203.

When the control chip CC is a vertically-conducting element, anadditional connection conductor can be provided; and a new terminal canbe provided at the side of the external connection terminals 223 and225. In such a case, the base 170 may be a metal, a ceramic, or a resin.The back electrode of the control chip CC and the new externalconnection terminal are bonded by the connection conductor.

In the electronic device 8B shown in FIG. 16B, the control chip CC ismounted on the base 170. The third inductor chip Ci3 is mounted on thecontrol chip CC. The second inductor chip Ci2 is bonded on the thirdinductor chip Ci3 so that the first coil 15 and the second coil 25 aremagnetically coupled. For example, the third inductor chip Ci3 ismounted on the control chip CC after the second inductor chip Ci2 isbonded to the third inductor chip Ci3.

For example, the control chip CC is sealed with the resin member 165 onthe base 170. The first connection conductor 201, the second connectionconductor 203, the third connection conductor 205, and the fourthconnection conductor 207 extend inside the resin member 165 from a backsurface of the resin member 165 at the side opposite to the base 170.The first connection conductor 201 and the second connection conductor203 are electrically connected respectively to the first and secondconnection terminals 113 and 115 of the third inductor chip Ci3. Thethird connection conductor 205 and the fourth connection conductor 207are electrically connected respectively to the input terminal 151 andthe output terminal 153 of the control chip CC.

The dielectric substrate 220 is connected on the back surface of theresin member 165 after the connection pad 213 that electrically connectsthe first connection conductor 201 and the third connection conductor205 is formed on the back surface of the resin member 165. Theconnection pad 213 is provided between the resin member 165 and thedielectric substrate 220.

The first external terminal 223 and the second external terminal 225 areprovided on the surface of the dielectric substrate 220 at the sideopposite to the resin member 165. For example, the first externalterminal 223 extends through the dielectric substrate 220 and iselectrically connected to the fourth connection conductor 207. Forexample, the second external terminal 225 extends through the dielectricsubstrate 220 and is electrically connected to the second connectionconductor 203.

The first connection terminal 113 of the third inductor chip Ci3 iselectrically connected to the input terminal 151 of the control chip CCvia the first connection conductor 201, the connection pad 213, and thethird connection conductor 205. The second connection terminal 115 iselectrically connected to the second external terminal 225 via thesecond connection conductor 203.

In the examples described above, the input signal that is input from thesecond external terminal 225 is input to the second coil 25 via thesecond connection terminal 115 and is output from the first connectionterminal 113 via the magnetic coupling between the first coil 15 and thesecond coil 25. The control chip CC receives, at the input terminal 151,the output of the first connection terminal 113 input via the firstconnection conductor 201, the connection pad 213, and the thirdconnection conductor 205. The control chip CC outputs a correspondingoutput signal from the output terminal 153. The output signal of thecontrol chip CC is output to the first external terminal 223 via thefourth connection conductor 207.

Third Embodiment

FIG. 17 is a schematic cross-sectional view showing an electronic device9A according to a third embodiment.

As shown in FIG. 17 , the electronic device 9A includes the firstsubstrate 100, the first insulating film 13, the first coil 15, thesecond insulating film 23, the second coil 25, a first connectionconductor 233, and a second connection conductor 235.

The first substrate 100 is, for example, a silicon substrate. The firstsubstrate 100 includes a first portion 100 a and a second portion 100 bthat are separated from each other. The first insulating film 13 isprovided on the first substrate 100. The second insulating film 23 isprovided on the first insulating film 13.

The first insulating film 13 includes the first coil 15. The secondinsulating film 23 includes the second coil 25. The second insulatingfilm 23 is bonded to the first insulating film 13 so that the first coil15 and the second coil 25 are magnetically coupled.

The first insulating film 13 has a back surface that contacts the firstsubstrate 100, and a front surface that contacts the second insulatingfilm 23. The first insulating film 13 further includes the connectingline 119 and a connection terminal 117. The connecting line 119 isprovided in the first insulating film 13 and extends in a directionalong the front surface of the first insulating film 13. The connectionterminal 117 is provided at the front surface side of the firstinsulating film 13 and is electrically connected to the connecting line119 via the contact plug 19 d.

The second insulating film 23 has a front surface that contacts thefirst insulating film 13, and a back surface at the side opposite to thefront surface. The second insulating film 23 further includes the secondconnection terminal 127 that is provided at the front surface side ofthe second insulating film 23 and is electrically connected to thesecond coil 25 via a contact plug 28.

The first insulating film 13 and the second insulating film 23 arebonded so that the front surfaces of the first and second insulatingfilms 13 and 23 contact each other, and the connection terminal 117 andthe second connection terminal 127 contact each other. The connectionterminal 117 and the second connection terminal 127 are bonded betweenthe first insulating film 13 and the second insulating film 23.

The length of the first insulating film 13 in a direction along thefront surface of the first insulating film 13 (e.g., the X-direction) isgreater than the length in the same direction of the second insulatingfilm 23. The first connection conductor 233 and the second connectionconductor 235 are provided on the front surface of the first insulatingfilm 13. The first connection conductor 233 and the second connectionconductor 235 are provided respectively on the portions of the firstinsulating film 13 that do not contact the second insulating film 23.The first connection conductor 233 and the second connection conductor235 are, for example, metal pillars including copper. For example, thesecond insulating film 23 is provided between the first connectionconductor 233 and the second connection conductor 235.

The first connection conductor 233 is electrically connected to thefirst coil 15, for example, via the contact plug 19 b. The secondconnection conductor 235 is electrically connected to the second coil25, for example, via the contact plug 19 c, the connecting line 119, thecontact plug 19 d, the connection terminal 117, the second connectionterminal 127, and the contact plug 28.

As shown in FIG. 17 , the first insulating film 13 includes a firstregion that is positioned between the first connection conductor 233 andthe first portion 100 a of the first substrate 100, and a second regionthat is positioned between the second connection conductor 235 and thesecond portion 100 b of the first substrate 100. The first coil 15 islocated between the first region and the second region. For example, aspacing WS between the first portion 100 a and the second portion 100 bof the first substrate 100 is greater than the coil diameter D1 of thefirst coil 15 (referring to FIG. 2A).

The electronic device 9A further includes a first resin member 243 and asecond resin member 245. The first resin member 243 is provided at theback surface side of the first insulating film 13 and covers the firstsubstrate 100. The first resin member 243 includes a portion that isprovided between the first portion 100 a and the second portion 100 b ofthe first substrate 100. The second resin member 245 covers the secondinsulating film 23 at the front surface side of the first insulatingfilm 13. The first connection conductor 233 and the second connectionconductor 235 extend inside the second resin member 245 and include endsurfaces that are not covered with the second resin member 245.

A method for manufacturing the electronic device 9A according to thethird embodiment will now be described with reference to FIGS. 18A to19C. FIGS. 18A to 19C are schematic cross-sectional views showingmanufacturing processes of the electronic device 9A according to thethird embodiment.

As shown in FIG. 18A, the fourth inductor chip Ci4 is bonded on thefirst insulating film 13 after the first insulating film 13 is formed onthe first substrate 100. The first insulating film 13 includes the firstcoil 15 and the connecting line 119 (referring to FIGS. 12A to 12C).

As shown in FIG. 18B, the second substrate 20 of the fourth inductorchip Ci4 is selectively removed. The second substrate 20 is removed by,for example, wet etching.

As shown in FIG. 18C, the first connection conductor 233 and the secondconnection conductor 235 are formed respectively on the first and secondconnection terminals 113 and 115 that are formed on the first insulatingfilm 13. The first connection conductor 233 and the second connectionconductor 235 are formed by, for example, plating.

For example, the first and second connection conductors 233 and 235 areformed using the same material as the materials of the first and secondconnection terminals 113 and 115. The first connection conductor 233 andthe first connection terminal 113 are joined together; and the secondconnection conductor 235 and the second connection terminal 115 arejoined together.

As shown in FIG. 19A, the second resin member 245 is provided at thefront surface side of the first insulating film 13 to cover the secondinsulating film 23, the first connection conductor 233, and the secondconnection conductor 235. The end surfaces of the first and secondconnection conductors 233 and 235 are exposed by polishing the frontsurface of the second resin member 245. The second resin member 245 is,for example, an epoxy resin.

As shown in FIG. 19B, the first insulating film 13 is partially exposedby selectively removing the first substrate 100 at the back surface sideof the first substrate 100. The first substrate 100 is selectivelyremoved by, for example, wet etching using a not-illustrated etchingmask.

As shown in FIG. 19C, the first resin member 243 is formed at the backsurface side of the first insulating film 13 to cover the firstsubstrate 100. The first resin member 243 is, for example, an epoxyresin.

FIG. 20 is a schematic cross-sectional view showing an electronic device9B according to a modification of the third embodiment. The electronicdevice 9B includes the first substrate 100, the first insulating film13, the first coil 15, the second insulating film 23, the second coil25, the first connection conductor 233, and the second connectionconductor 235.

The first substrate 100 is, for example, a silicon substrate. The firstinsulating film 13 is provided on the first substrate 100, and thesecond insulating film 23 is bonded on the front surface of the firstinsulating film 13. The second insulating film 23 is bonded so that thefirst coil 15 and the second coil 25 are magnetically coupled. The firstconnection conductor 233 and the second connection conductor 235 areprovided at the front surface side of the first insulating film 13. Asshown in the example, the first substrate 100 may be provided to have acontinuous body at the back surface side of the first insulating film13.

According to the embodiment, it is possible to reduce the height of thecircuit board on which the electronic devices 9A or 9B is flip-chipmounted.

Fourth Embodiment

FIG. 21 is a schematic cross-sectional view showing an electronic deviceaccording to a fourth embodiment. FIG. 21 illustrates a cross section ofthe first inductor chip Ci1.

As shown in FIG. 21 , the first inductor chip Ci1 may include a circuitportion 310 provided at the front surface side of the first substrate10. The first coil 15 is electrically connected to the circuit portion310. The first connection terminal 17 a is electrically connected to thecircuit portion 310 via the contact plug 19 a.

For example, the circuit portion 310 outputs a current flowing in thefirst coil 15 which corresponds to the signal input via the firstconnection terminal 17 a. The circuit portion 310 may be configured tooutput, via the first connection terminal 17 a, a signal correspondingto the current flowing in the first coil 15.

The second inductor chip Ci2 also may include a circuit portion(not-illustrated) provided at the front surface side of the secondsubstrate 20. The first inductor chip Ci1 that is shown in theembodiment also is applicable to the first inductor chip Ci1 of theother embodiments.

FIG. 22 is a circuit diagram illustrating the electronic device 300according to the fourth embodiment. The electronic device 300 includesthe first inductor chip Ci1 and the second inductor chip Ci2 (referringto FIG. 1 ).

In the example, the first inductor chip Ci1 includes a first coil 15-1and another first coil 15-2. The second inductor chip Ci2 includes asecond coil 25-1 and another second coil 25-2. The first coil 15-1 andthe first coil 15-2 are provided inside the first insulating film 13.The second coil 25-1 and the second coil 25-2 are provided inside thesecond insulating film 23.

As shown in FIG. 22 , the first coil 15-1 is magnetically coupled withthe second coil 25-2. The first coil 15-2 is magnetically coupled withthe second coil 25-1.

The electronic device 300 further includes, for example, a first circuit320 and a second circuit 330. The first circuit 320 includes adifferential driver circuit 315, a capacitance C1, and a capacitance C2.The second circuit 330 includes a differential receiving circuit 325, acapacitance C3, and a capacitance C4.

The first circuit 320 is provided, for example, at the front surfaceside of the first substrate 10. The first circuit 320 is providedbetween the first substrate 10 and the first insulating film 13. Thesecond circuit 330 is provided, for example, at the front surface sideof the second substrate 20. The second circuit 330 is provided betweenthe second substrate 20 and the second insulating film 23.

One end of the first coil 15-1 is connected to a first constantpotential. The other end of the first coil 15-1 is connected to thecapacitance C1. One end of the first coil 15-2 is connected to a secondconstant potential. The other end of the first coil 15-2 is connected tothe capacitance C2.

One output of the differential driver circuit 315 is connected to thecapacitance C1. Another output of the differential driver circuit 315 isconnected to the capacitance C2. The capacitance C1 is connected betweenthe differential driver circuit 315 and the first coil 15-1. Thecapacitance C2 is connected between the differential driver circuit 315and the first coil 15-2.

One end of the second coil 25-1 is connected to a third constantpotential. The other end of the second coil 25-1 is connected to thecapacitance C4. One end of the second coil 25-2 is connected to a fourthconstant potential. The other end of the second coil 25-2 is connectedto the capacitance C3.

The first, second, third, and fourth potentials may be the samepotential. The first and second potentials are the same potential. Also,the third and fourth potentials are the same potential. The first andsecond potentials are desirable to be different from the third andfourth potentials.

One input of the differential receiving circuit 325 is connected to thecapacitance C3. The capacitance C3 is provided between the second coil25-2 and the input of the differential receiving circuit 325. The otherinput of the differential receiving circuit 325 is connected to thecapacitance C4. The capacitance C4 is provided between the second coil25-1 and the input of the differential receiving circuit 325.

An operation of the electronic device 300 will now be described. In FIG.22 , Vin is the modulated input signal. For example, an edge-triggeredtechnique or on-off keying is used to modulate the input signal. In anymethod, Vin is the high frequency signal including the modulatedoriginal signal.

The differential driver circuit 315 outputs a current i0 flowing in thefirst coils 15-1 and 15-2. The current i0 corresponds to Vin, and flowsin mutually-reverse directions respectively in the first coils 15-1 and15-2. The first coils 15-1 and 15-2 generate magnetic fields (H1) havingmutually-reverse orientations. When the number of winds of the firstcoil 15-1 is equal to the number of winds of the first coil 15-2, themagnitudes of the generated magnetic fields are equal.

The induced voltage generated in the second coil 25-1 by the magneticfield H1 has the reverse direction to the induced voltage generated inthe second coil 25-2 by the magnetic field H1. In the second coils 25-1and 25-2, a current i1 flows. The magnitude of the induced voltagegenerated in the second coil 25-1 is equal to the magnitude of theinduced voltage generated in the second coil 25-2. Positive and negativevoltages are input to the differential receiving circuit 325. In otherwords, the induced voltages that are generated in the second coils 25-1and 25-2 are applied respectively to the inputs of the differentialreceiving circuit 325. One of the input induced voltages is reversed;and 2 times the induced voltage is output as the demodulated signalVout.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the invention.

What is claimed is:
 1. An electronic device, comprising: a firstsubstrate; a first insulating film provided on the first substrate; afirst coil provided in the first insulating film; a second insulatingfilm provided on the first insulating film; a second coil provided inthe second insulating film, the first insulating film and the secondinsulating film contacting each other so that the first coil and thesecond coil are magnetically coupled, the second insulating film havinga front surface contacting the first insulating film, the secondinsulating film contacting a front surface of the first insulating film,the first insulating film including a first non-contact portion notcontacting the second insulating film, one of the first and secondinsulating films including a second non-contact portion not contactingthe second or first insulating film; a first terminal provided on thefront surface of the first insulating film at the first non-contactportion, the first terminal being electrically connected to the firstcoil; a second terminal provided on the front surface of the secondinsulating film at the second non-contact portion, the second terminalbeing electrically connected to the second coil; a resin member sealingthe first substrate, the first insulating film, the second insulatingfilm, the first terminal, and the second terminal; a first externalterminal provided on a first surface region of the resin member andelectrically connected to the first terminal; a second external terminalprovided on a second surface region of the resin member and electricallyconnected to the second terminal, the second external terminal beingapart from the first external terminal; a first contact plugelectrically connecting the first terminal and the first externalterminal, the first contact plug extending straight in the resin membertoward the first terminal; and a second contact plug electricallyconnecting the second terminal and the second external terminal, thesecond contact plug extending straight in the resin member toward thesecond terminal.
 2. The device according to claim 1, further comprising:a second substrate provided on the second insulating film, the secondinsulating film including a portion positioned between the firstinsulating film and the second substrate.
 3. The device according toclaim 1, further comprising: a circuit provided between the firstsubstrate and the first insulating film and electrically connected tothe first coil.
 4. The device according to claim 3, wherein the circuitis electrically connected to the first external terminal via the firstterminal and the first contact plug.
 5. The device according to claim 1,wherein the resin member has a top surface and a bottom surface oppositeto the top surface, the first external terminal being provided on thefirst surface region in the top surface, the second external terminalbeing provided on the second surface region in the bottom surface. 6.The device according to claim 1, wherein the resin member includes asurface crossing a direction from the first substrate toward the secondinsulating film, the surface of the resin member including the firstsurface region and the second surface region, and the first externalterminal and the second external terminal are provided on the surface ofthe resin member.
 7. The device according to claim 5, furthercomprising: An electronic device, comprising: a first substrate; a firstinsulating film provided on the first substrate; a first coil providedin the first insulating film; a second insulating film provided on thefirst insulating film; a second coil provided in the second insulatingfilm, the first insulating film and the second insulating filmcontacting each other so that the first coil and the second coil aremagnetically coupled, the second insulating film having a front surfacecontacting the first insulating film, the second insulating filmcontacting a front surface of the first insulating film, the firstinsulating film including a first non-contact portion not contacting thesecond insulating film, one of the first and second insulating filmsincluding a second non-contact portion not contacting the second orfirst insulating film; a first terminal provided on the front surface ofthe first insulating film at the first non-contact portion, the firstterminal being electrically connected to the first coil; a secondterminal provided on the front surface of the second insulating film atthe second non-contact portion, the second terminal being electricallyconnected to the second coil; a first connection conductor connected tothe first terminal, the first connection conductor being electricallyconnected to the first coil via the first terminal; a second connectionconductor connected to the second terminal, the second connectionconductor being electrically connected to the second coil via the secondterminal; a resin member sealing the first substrate, the firstinsulating film, the second insulating film, the first connectionconductor, and the second connection conductor; a first externalterminal provided on a first surface region of the resin member andelectrically connected to the first connection conductor; a secondexternal terminal provided on a second surface region of the resinmember and electrically connected to the second connection conductor,the second external terminal being apart from the first externalterminal; and a third substrate including the first external terminaland the second external terminal, the resin member being provided on thethird substrate, the first connection conductor and the secondconnection conductor extending in the resin member, the first connectionconductor electrically connecting the first terminal and the firstexternal terminal, the second connection conductor electricallyconnecting the second terminal and the second external terminal.
 8. Anelectronic device, comprising: a first substrate; a first insulatingfilm provided on the first substrate; a first coil provided in the firstinsulating film; a second insulating film provided on the firstinsulating film; a second coil provided in the second insulating film,the first insulating film and the second insulating film contacting eachother so that the first coil and the second coil are magneticallycoupled, the second insulating film having a front surface contactingthe first insulating film, the second insulating film contacting a frontsurface of the first insulating film, the first insulating filmincluding a first non-contact portion not contacting the secondinsulating film, one of the first and second insulating films includinga second non-contact portion not contacting the second or firstinsulating film; a first terminal provided on the front surface of thefirst insulating film at the first non-contact portion, the firstterminal being electrically connected to the first coil; a secondterminal provided on the front surface of second insulating film at thesecond non-contact portion, the second terminal being electricallyconnected to the second coil; a first connection conductor connected tothe first terminal, the first connection conductor being electricallyconnected to the first coil via the first terminal; a second connectionconductor connected to the second terminal, the second connectionconductor being electrically connected to the second coil via the secondterminal; a resin member sealing the first substrate, the firstinsulating film, the second insulating film, the first connectionconductor, and the second connection conductor; a first externalterminal provided on a first surface region of the resin member andelectrically connected to the first connection conductor; a secondexternal terminal provided on a second surface region of the resinmember and electrically connected to the second connection conductor,the second external terminal being apart from the first externalterminal; a third substrate including the first external terminal andthe second external terminal; a control element electrically connectedto the first coil via the first connection conductor; and a thirdconnection conductor electrically connecting the control element and thefirst external terminal, the resin member being provided on the thirdsubstrate, the first connection conductor, the second connectionconductor, and the third connection conductor extending in the resinmember, the second connection conductor electrically connecting thesecond terminal and the second external terminal.
 9. The deviceaccording to claim 8, wherein the first substrate is mounted on thecontrol element.
 10. The device according to claim 8, furthercomprising: a heat dissipation base connected to the control element,the resin member being provided between the heat dissipation base andthe third substrate.
 11. The device according to claim 10, wherein thefirst substrate is connected to the heat dissipation base, the firstsubstrate being apart from the control element.
 12. An electronicdevice, comprising: a first substrate; a first insulating film providedon the first substrate; a first coil provided in the first insulatingfilm; a second insulating film provided on the first insulating film; asecond coil provided in the second insulating film, the first insulatingfilm and the second insulating film contacting each other so that thefirst coil and the second coil are magnetically coupled, the secondinsulating film having a front surface contacting the first insulatingfilm, the second insulating film contacting a front surface of the firstinsulating film, the first insulating film including a first non-contactportion not contacting the second insulating film, one of the first andsecond insulating films including a second non-contact portion notcontacting the second or first insulating film; a first terminalprovided on the front surface of the first insulating film at the firstnon-contact portion, the first terminal being electrically connected tothe first coil; a second terminal provided on the front surface of thesecond insulating film at the second non-contact portion, the secondterminal being electrically connected to the second coil; a firstconnection conductor connected to the first terminal, the firstconnection conductor being electrically connected to the first coil viathe first terminal; a second connection conductor connected to thesecond terminal, the second connection conductor being electricallyconnected to the second coil via the second terminal; and a first resinmember covering the second insulating film and the first and secondconnection conductors on the first insulating film, the secondconnection conductor being connected to the second terminal on the frontsurface of the first insulating film, the first connection conductor andthe second connection conductor including end surfaces not covered withthe first resin member.
 13. The device according to claim 12, furthercomprising: a second resin member covering the first substrate, thefirst insulating film and the second insulating film being providedbetween the first resin member and the second resin member, the firstsubstrate including a first portion, and a second portion apart from thefirst portion, the first insulating film including a portion between thefirst connection conductor and the first portion of the first substrateand another portion between the second connection conductor and thesecond portion of the first substrate, the second resin member includinga portion positioned between the first portion and the second portion,the first coil and the second coil being positioned between the firstresin member and the portion of the second resin member.
 14. The deviceaccording to claim 12, wherein the first terminal and the firstconnection conductor are combined into one body, and the second terminaland the second connection conductor are combined into another one body.